title: Hormone replacement therapy increases the risk of cranial meningioma.
abstract: OBJECTIVE
  We investigated the influence of hormone replacement therapy (HRT) use on the risk of meningioma in a population-based setting.
  
  
  METHODS
  We conducted a nationwide case-control study in Denmark based on population-based administrative and health registries. The study included all female patients aged 55-84 years with a first time diagnosis of meningioma during 2000-2009. The cases were matched on birth year with female population controls. Ever use of HRT since 1995 was defined as ≥2 HRT prescriptions and categorised according to HRT type (oestrogen only, combined oestrogen-progestagen, and progestagen only) and cumulated duration of use (<1, ≥1 to <5, ≥5 to <10, ≥10 years). We used conditional logistic regression to compute odds ratios (ORs), with 95% confidence intervals (CIs), for meningioma associated with HRT use, and adjusting for potential confounders.
  
  
  RESULTS
  We identified 924 cases and 6122 controls. Ever use of HRT was associated with an increased risk of meningioma (OR, 1.3; 95%CI, 1.1-1.5) compared with non-use (0-1 prescriptions). The risk increased with increasing duration of HRT use, reaching an OR of 1.7 (95% CI, 1.2-2.3) after more than 10 years of use. The risk of meningioma associated with long-term (≥10 years) HRT use was most pronounced for combined oestrogen-progestagen therapy (OR, 2.2; 95% CI, 1.4-3.3), especially when this regimen constituted the sole HRT therapy (OR, 2.7; 95% CI, 0.9-7.5), although the latter estimate was based on small numbers.
  
  
  CONCLUSIONS
  Long-term HRT use, particularly of combined oestrogen-progestagen therapy, may increase the risk of meningioma.
authors.affiliation: Department of Neurology, Odense University Hospital, Institute of Clinical Research, Faculty of Health Sciences, University of Southern Denmark, Sdr. Boulevard 29, 5000 Odense C, Denmark.
authors.forename: Lene
authors.initials: L
authors.lastname: Andersen
authors.forename: Søren
authors.initials: S
authors.lastname: Friis
authors.forename: Jesper
authors.initials: J
authors.lastname: Hallas
authors.forename: Pernille
authors.initials: P
authors.lastname: Ravn
authors.forename: Henrik Daa
authors.initials: HD
authors.lastname: Schrøder
authors.forename: David
authors.initials: D
authors.lastname: Gaist
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D016022:Case-Control Studies; D015331:Cohort Studies; D003718:Denmark / Q000453:epidemiology; D005260:Female; D020249:Hormone Replacement Therapy / Q000009:adverse effects / Q000706:statistics & numerical data*; D006801:Humans; D008577:Meningeal Neoplasms / Q000139:chemically induced / Q000453:epidemiology*; D008875:Middle Aged; D012307:Risk Factors; D013120:Spinal Cord Neoplasms / Q000139:chemically induced / Q000453:epidemiology*
keywords: Brain tumour epidemiology; Case–control study; Hormone replacement therapy; Meningioma; Risk